With respect to micro speaker modules, in general, module devices are asymmetrical. Meanwhile, it is difficult to avoid process tolerance in a micro speaker module assembling process, which will usually cause polarization of a diaphragm of a micro speaker in a case of large displacement. The polarization is mainly shown in a way that displacements of four corner locations of a reinforcing part are different. That is, the displacements of a diaphragm plane in a vibration direction are not uniform.
Moreover, requirements on internal magnetic gaps and external magnetic gaps are higher and higher in the market, and the increasingly reduced magnetic gaps will become more and more sensitive to the polarization of the diaphragm.
The polarization of the diaphragm will bring the following problems.
(1) Non-uniform displacements in the vibration direction will cause distributed stress of the diaphragm plane. As a result, stress of a local block is likely to become overlarge, resulting in excessive fatigue, even cracking of the diaphragm.
(2) The non-uniform displacements in the vibration direction will also cause deflection of a voice coil between in a magnetic gap, such that the voice coil will have frictional collision with a magnetic circuit.
At present, spider are adopted in micro speakers to alleviate polarization of products. Although the spider restrains polarization mainly through a mechanical restoring force, it will occupy a certain space. Meanwhile, a process for applying the spider to the micro speakers faces greater challenges.